This invention relates to the chlorination of aluminous material to form aluminum chloride and more particularly to the chlorination of aluminous material in the presence of a particular solid reducing agent.
It is known to chlorinate aluminous material in the presence of solid reducing agents. One aspect of such a reaction which significantly influences the completeness of the reaction is the manner of bringing about contact of the reactants. Techniques which have been used to bring the aluminous material and the reducing agent into sufficiently intimate contact to promote chlorination include mixing a specially treated carbon source with the aluminous material, briquetting a carbon-alumina mixture or coating the aluminous material with a liquid hydrocarbon.
McAfee (U.S. Pat. No. 2,084,290) describes as the "oldest method for the manufacture of aluminum chloride", subjecting a mixture of hot carbon and alumina in a heated retort to the action of chlorine. It is this basic process which must be modified and improved to make the production of aluminum chloride more efficient and economic. In this vein, use of even cheaper or less pure reactant materials is being evaluated and explored. Becker et al (U.S. Pat. No. 4,105,752), for example, disclose a method for chlorinating aluminous material in which activated carbon derived from coal is used. In their procedure, Becker et al prepare activated carbon by contacting coal with an acidic leaching solution, removing the greater portion of the leaching solution and calcining this treated coal at 550.degree.-775.degree. C. While this procedure does successfully utilize a cheaper starting material, it also requires a significant amount of pretreatment of the carbon source before mixing with the aluminous material.
It would be particularly advantageous to have a carbon reductant suitable for use in a chlorination reaction, which reductant is readily available and requires minimal pretreatment.